wat about in... control panel/admin tools/event viewer... i remember wen i used a realy realy old 4gig disk, there would be an entry in event viewer warning me that the disk is about to fail. i know yours isnt that old, but maybe there is an entry in there that may give u some clues.
some one else can prolly better help u to retrieve ur data if posible.
but if u wont to format it, u maybeable to by using Disk part... unless it doesnt recognize it like disk manager.
in the command prompt, Start/accessories/command prompt... type (diskpart), then (list disk), and see if its listed.u can format it from there, but i forget the exact perameters, thy can prolly be found on the net easily.